Switchboard plug and jack structure



Oct. 14, 1941. 1 SCHMlD SWITCHBOARD PLUG AND JACK STRUCTURE 2 sheets-sh'et 1 FIG. 3

Filed Jan. 6, 1940 FIG@ 1w 5 f l G 4 G F o .e a 2 .Nr..O n C h|||l| m um. um u n M. n I o 5 Q m 2ML@ m. 4 2 m M WM m mw. ma u, w. O /2 .I. 2 2 2 2 INVENTOR J. SCHMID ATTORNEY Oct. 14, 1941.

J. scHMlD SWITCHBOARD PLUG AND JACK. STRUCTURE 2 sheets-sheet 2' Filed Jan.

INVENTOR J. scHMlo ATTORNEY Patented Qct. 14,

il ii 1 sra'res SIVI'lCHBOAR-l)I PLUG AND JACK STRUCTURE `oseph Schmid, New York, Y., assigner to The Western Union Telegraph Company, New York, N. Y., a corporation of New York Application `lanuary 6, 1940, Serial No. 312,679

8 'Claims'.

This invention relates generally to `a multiple circuit plug and jack structure, and more particularly to a switchboard plug and jack adapted for connecting or switching a plurality of telegraph or other communication circuits.

Various types of switchboard plug and jack structures have'heretofore been employed in Vtelephone and telegraph systems, but they have lexhibited various disadvantages, among which are that if the structures were suiciently small and compact to be practical, not sulcient clearance was obtainable between adjacent terminals both on the plug and jack, particularly when a relatively large number of circuits were to be controlled thereby, so that dirt, pieces of wire, solder, and other foreign substances that are apt to be present at various times were likely to` cause grounds, short-circuits, or crosses between adjacent circuits. Also, the prior art devices have in general been difficult toinspect and repair, especially when in their operative positions inthe switchboard, and have been subject to undue wear and misalignment of the contact elements so that high resistance or loose connections frequently have resulted.

An object of the present invention is to obviate various of the disadvantages heretofore present, and to provide a plug and jack structure which is compact and yet is sufciently rugged to stand rough handling in service, andwhich is capable of carrying relatively heavy currents, and in which the various connecting parts and termi` nals more readily are available for inspection, repair or replacement purposes.

Another object is a plug and jack structure which may handle a relatively large number of circuits and which may be assembled from a relatively small number of like parts.

A further object is a plug and jack structure of the character described which may be-built or assembled with a minimum of skill on the part of workers during'the manufacture thereof, and in which larger tolerances are permissible without adversely aifecting the high standardr of performance required. l

Still another object is a jack structure ofthe character disclosed which may be mounted more readily, and in which the jacks are readily interchangeable in a switchboard structure.

Gther and further advantages of the invention will be apparent from the following description of the apparatus, taken in connection with the accompanying drawings, in which:

Fig. l is a view of a telegraph switchboardemploying plug and jack structures constructed in accordance with theinvention;

Fig. 2 is a longitudinal sectional View of one of the plugs inserted into a jack in circuit connecting position, taken along the line 2-2 of Fig. 1;

Fig'. 3 is a front view of one 'of the jacks of l 'and 2, with the plug removed from the la@ 5 Fig. 4 is a longitudinal section, taken along the line 4 4 of Fig. 3

Fig; 5 is a fragmentary top view of the jack, showing certain details of the switchboard panel structure; g

Fig; 6 isa view of the plug and jack, with the plug removed from the Vjack Fig. 7 is a cross-section taken along the line 1-7gofFig. 6,rshowing certain details of the plug structure; e Fig. Y8 is Aa crosssection taken along the line 8--8 of Fig. 6;

Figs', 9 and l0 are views showing various groups of contacts of the jack structure as they are progressively moved outwardly by the plug when it is inserted into the jack;

Fig. 11 is a cross-section taken along the line I I -l I of Fig. 2, showing the positions of the jack contacts when the plug is fully inserted; and

Fig'.- 12 is a fragmentary View of a plug having a different form of keyway therein.

Referring now to Fig. l of the drawings, there is shown a telegraph switchboard structure comprising upper and lower supporting iron strips 2) secured in place by vertical iron strips 2l, one of which vertical strips is shown in the figure. The vertical strips are secured to a switchboard supporting framework in any suitable manner, asr by screws or bolts which pass through the holes 22 in -the vertical strips. Each of the laterally extending strips 2U has a series 4of tongues 20d, the upperl and lower aligned tongues providing mounting means for the channel-shaped jack mounting strips 24, Figs. l and 5, which are secured to the tongues 20a by means of machine screws-25,- Figsfl and 2. that pass through holes 26 in the tongues and are screw-threaded into the tongues.

As hereinafter described in detail, the jacks A23 are mounted in openings 24a in the faces ofthe channel-shaped members 2d, each of the strips being adapted to mount four jacks, so that the portion of the switchboard assembly shown pro vides room for sixteen jacks. In the ligure, only the upper openings 24a of the strips are shown as having jacks mounted therein, these jacks having their complementary switchboard plugs 21 inserted Atherein in operating position. The other three openings of each of the mounting strips 2# are covered by removable Vblanlr caps 28 which may be removably secured in the openings Zdo by a forcent or by spring tongues o1I any othersuitable manner. The switchboard may thus be built up to accommodate any desired number of working circuits, and also provides ample room for future expansion.

Figs. 2 to 6 shoW various details of the jack structure and 'mounting means therefor, and' Figs. 2 and 6 also show various details of the plug structure.

In the embodiment illustrated, the jack com prises a cylindrical shell 30 of Bakelite, hard rubber, or other suitable material, the front end of the shell being mounted in a close-fitting circular opening in a plug 3| of suitable insulating material, Figs. 2 to 4, and rmly secured thereto by three machine screws 32 that pass through the plug 3| and are screw-threaded into the front end of the shell 30, the ends of the screws stopping short of the inner surface of the shell. Each plug 3| is firmly secured to its jack mounting strip 24 by four machine screws 33, Figs. 3, 5 and 6, that pass through holes in the two sides or flanges 24a of the mounting strip andare screw-threaded into the plug 3|, the plug fitting snugly between the two flanges 24a.

Referring again to Figs. 2, 4 and 6 of the drawings, the shell of the jack has mounted, on its outer cylindrical surface, a series of similar contact spring assemblies, each such assembly comprising a fixed U-shaped contact member 35, secured, as by pins in the manner shown in Fig. 2, to the body of the shell 30. The contact has an upturned portion or lug at one end for receiving a conductor c soldered thereto, and at its other end has an upturned portion or lug adapted to close a circuit when its associated spring contact 36 is in contact with the lug, as shown in Figs. 4 and 6. Each contact spring 36 is rigidly mounted on the shell 36 by means of two machine screws 38 that pass through holes in the spring and thread into the shell 30. A

spacing strip 39 of insulation is interposed between the spring and shell to suitably space the spring therefrom, and a small strip 40 of metal prevents injury to or breakage of the spring when flexed, and also provides a stiffening piece for the spring. The rear end of each contact spring 36, which extends beyond the rear end of the shell 30, provides means for soldering a conductor c to the spring, which conductor forms a portion of the circuit controlled by the plug and jack. Passing through and rigidly secured to the front end of each contact spring, in any suitable manner, as by riveting or spinning over an end thereof, is a generally cylindrical contact member 42. Each of the members 42 extends, through a circular opening 43 in the wall of the shell 30, into the interior of the shell lto make contact with the plug when it is inserted, sulficient clearance being provided to enable the member 42 to move freely within the opening as its spring 36 is actuated. i

In the particular jack illustrated, fourteen spring contact assemblies are provided, so that fourteen circuits may be controlled thereby, al-

CTX

the circuits of the plug. Such an arrangement enables the conditioning or operation lof certain apparatus before other apparatus in the circuits is conditioned or operated, thereby providing a desired sequence of operations of the equipment controlled by the plug and jack. By staggering the contact springs 36 and their associated xed contacts 35 in the manner shown, there is also provided a greater clearance between adjacent contacts and thus minimizes the possibility 0f short-circuits, crosses or grounds, and facilitates soldering the external connections c to the lugs of the contacts 35. A metal key 46, shown in Figs. 2 and 3, is inserted in a slot in the inner front end of the sleeve 30 and is secured thereto by two machine screws 41 which pass through the plug 3|. This key co-acts with a keyway in the plug structure so that the plug can only be inserted when it is in a predetermined position with respect to the jack, and thus insure proper connection of the respective circuits.

Referring to Figs. 2 and 6, the plug 2`| comprises a substantially solid cylindrical core 5| of Bakelite or other suitable insulating material, having longitudinal slots 53 cut or otherwise formed in the outer peripheral surface, which slots receive and hold bars 52, preferably of Phosphor bronze, that provide means for connecting the plug circuits to the vari-ous contact members 42 of the jack, in the manner shown in Fig. 2. The bars 52 have indented or recessed portions 52a into which the contacts 42 t when the plug is fully inserted in the jack. Between the slots 53, and intermediate the contact bars 52, the plug body has slotted portions 54 to enable the contact members 42 to iit in the p0rti-ons 52a of the bars 52, the portions 54 also forming the sides of the slots 53 and providing supporting means for the sides of the various bars. The bars may be slightly wedge-shaped, with the narrower edges of the bars received in the slots 53, so as to firmly wedge the bars in place and also to provide greater clearance between adjacent bars at the surfaces 54 of the plug body 5|, as shown in Fig. 6, the outer edges of the bars 52 are flush with the outer perimeter of the body 5|.

The tip end of the plug body has secured thereto, by a machine screw and nut 66, a

though it will be understood that the number of contact assemblies will vary depending upon the number and nature of the circuits employed. The various circuits may comprise, for example, different channels of a multiplex system,to gether with auxiliary circuits associated therewith, or may comprise variousother kinds of circuits which may or may not be thus closely interrelated. Also, as shown, the circuits controlled by each jack normally are closed when no plug is inserted in the jack so that the circuits will not inadvertently be left open at vthe jacks, and the contacts 42 and associated springs 36 may be staggered longitudinally of the shell 30 so as to form three groups of contact controlling assemblies, whereby when the plug is inserted these groups are switched successively to tapered end piece 6| of suitable insulating material, the member 6| serving to `guide the plug into the jack. The member 6| has formed thereon Aa flanged portion 6|a which, as shown in Fig.

2, fits closely `over reduced end portions 52a of the bars 52 and thus securely clamps the forward end of each of the bars in proper position. The metal tip 63, which is secured in a recess in the member 6|, as by the pins shown in Fig. 2, has a recessed portion therein that provides a keyway which slides over the key 46 of the jack when the plug is inserted therein. A slotted portion 64 in the underside of the core 5| forms a continuation of the keyway so that the key 46 and the keyway formed by the portions 63 and 64 coact to insure that the plug will be inserted in proper position relative to the jack and that the plugswill not turn in the jack after it is inserted therein. Preferably, and as shown,

an insulating washer 65 is interposed between `cover the members l2.

rthese conductors being brazed, soldered yor otherwise secured to the ends of the bars 52. Flexible conductors d, Fig. 2, whichv are covered with braid or other suitable insulating material,- are connected to the conducto-rs Il by means of conducting sleeve members l2, the conductors d and 'il being received within the sleeves l2 and soldered or otherwise 4secured thereto. For convenience, the conducting sleeve l2 may be split longitudinally to facilitate entry of the solder around the conductors. Insulating sleeves 13 As shown in Figs. 2 and 7,'- the holes in the cap 68, through which the conductors H pass, have alternate ones with enlarged recessed portions so as to receive the ends of the insulating sleeves 73 within these recessed portion thereby to increase the leakage path between adjacent conductors. Member 68 has an eirteriorly threaded portion, by means of which is secured thereto a hollow cylindrical shell lil yof insulation through which the conductors d pass, this shell aiso forming a handle for the plug. Usually, and as shown, the conductors d are formed into a cord or cable e, the number of conductors corresponding to the number-of bars 52 whit-.hare used inthe plug.

The end of the handle or shell ill is closed by a circular collar 85 of brass or other suitable material, the collar having a flanged portion 85a that abuts against the end of the shell 1B, and a reduced portion 85h that ts within the end of the shell lil. The collar also has projecting therefrom a plurality of spring tongue members 85, these tongue members surrounding the opening in the collar through which thecord e passes.

The 4tongue members are arranged so that they taper inwardly and a collar 81 encirclesthe tongue members with a fairly close fit, so that as the member is moved towards the member 85, by means of the machine screws 88 which thread into the collar, the tongue members v86 will be forced inwardly to firmly clamp the cord e and thus prevent any pull from being exerted on the conductors d when the plug is inservice. The member 85 is secured to the shell 10 by means of` machine screws S3, Fig. 6, which pass through the shell and are screw-threaded into the reduced portion 85h of the collar;

Figs. 9, 10 and 11 show how the several groups of contacts on the jack are successively cono nected to the plug as it is 'inserted in the jack. In Fig. 9 the entry of the plug hasoperated the group of contacts 42a; as the plug is further inserted the group of contacts 42h are also operated, as shown in`Fig. 10; and in Fig. 11 the plug has been fully inserted and all of the contacts i2 have been operated. As hereinbefore stated, thiseffects any desired sequence of operations of the equipment controlled by the plug and jack. The number of the several groups, and the number of contacts in each of such groups, may obviously be varied to provide any desired control or sequence of operations.

Fig. l2 shows a modified form of plug in which the metal tip or keyway 63a, has an arcuate opening, instead of the rectangular opening in the member 63 shovm in Figs. 2 and 9 to 11. This prevents the plug of Fig. 12 from being inserted into a jack having a rectangular key 46, such as shown in Fig. 2. However, a plug having a rectangular tip or keyway 63 can be inserted in a jack having an arcuate key tta, such as the jack shown in the, upper left hand portion of Fig. l. The arrangement'is of especial importance in the use cf patching c'ords having a plug at each emi, since 'it prevents connecting circuits teg'thewhicli-re not intended or adaptedto be patching cord having thediierently formed tips or keyway's 63' and 63d. 0

While there-are shown and described herein certain preferred embodiments of the invention, many ther and varied forms and uses will occur teths-e yersed in the art without departing from the -invri-ticn, and the invention is, therefore, notlii'nited eiicept as indicated by the terms and scope of the appended claims.

Iclairmi f i. Switchboard plug and jack structure compri ng a Vvsupperting framework, a jack compris ng a shell having one end thereof secured to tiiefsupporti-ng framework and forming the front opening of rthe jack 'for receiving a plug., a

'plurality of circuit-controlling contact'meinbers 'mounted on the outer surface'of said jack shell andspacednaround the periphery of said shell, said shell having apertured portions therein adjacent -tdsaidi contact members, said contact mer'ribersv having contact'v elements 'projecting through said apertured portions into the vinterior of said shelland movable within said apertured portions, a plugk comprising a body of insulating material adapted to be inserted'in said jack shell, said plug lbody having a plurality of longitudinally extending slots in the outer surface thereof andspaced around the periphery of said body, conducting bars disposed in said slots and means forsecur-ing said bars in'place, the spacing of said bars around the periphery of the plug body corresponding to thespacing of the contact elementsV around the periphery of said jack shell Vwhereby when the plug is inserted a predetermined distance into the Yjack the various conducting bars will engage the various contact elements, respectively, to connect circuits through the plug and jack.

2. Switchboard plug and jack structure comprising a supporting framework, a jack comprising a `hollow cylindrical shell having one end thereof secured to the supporting framework and forming the front opening of the jack for receiving a plug, a plurality of circuit-controlling contact members mounted on the outer surface of 'said jack shell and spaced around the periph-ery of said shell, said shell having apertured portions therein adjacent to said contact members, said contact members having contact elements projecting through said apertured portions into the interior of said shell and movable within said apertured portions, a plug comprising a cylindricalbody of insulating material adapted to be inserted inl said jack'shell, said plug body having a plurality of longitudinally extending slots in the outer surface thereof and spaced around the periphery of said body, conducting bars disposed in said slots and lmeans forsecuring said bars in place, the spacing of said barsv around the periphery of the plug body corresponding to the spacing of the contact elements around the periphery of said jack shell whereby when the plug is inserted a predetermined distance into the jack the various conducting bars will engage the various contact elements, respectively, to connect circuits through the plug and jack, `and coacting means on the plug and jack structure preventing turning of the plug when inserted in the jack.

3. ASwitchboard plug and jack structure comprising a 'support-ing framework., a kjack comprising a shell having one end thereof secured to the supporting framework and forming the front opening of the jack for receiving a plug, a plurality of circuit-controlling spring contact members mounted on the outer surface of said jack shell and spaced around the periphery of said shell, said shell having apertured portions therein adjacent to said contact members, said contact members having contact elements projecting through said apertured portions into the interior of said shell and movable within said apertured portions, said spring contact members normally urging said contact elements inwardly, a plug comprising a body of insulating material adapted to be inserted in said jack shell, said plug body having a plurality of longitudinally extending slots in the outer surface thereof and spaced around the periphery of said body, conducting bars disposed in said slots and means for securing said bars in place, the spacing of said bars around the periphery of the plug body corresponding to the spacing of the contact elements around the periphery of said jack shell whereby when the plug is inserted a predetermined distance into the jack the various conducting bars will engage the various contact elements, respectively, to connect circuits through the plug and jack.

4. Switchboard plug and jack structure comprising a supporting framework, a jack comprising a shell having one end thereof secured to the supporting framework and forming the front opening of the jack for receiving a plug, a plurality of circuit-controlling contact members mounted on the outer surface of said jack shell and spaced around the periphery of said shell, said contact members being spaced longitudinally of the shell to provide different groups of these members, said shell having apertured portions therein adjacent to said contact members, said contact members having contact elements projecting through said apertured portions into the interior of said shell and movable within said apertured portions, a plug comprising a body of insulating material adapted to be inserted in said jack shell, said plug body having a plurality of longitudinally extending slots in the outer surface thereof and spaced around the periphery of said body, conducting bars disposed in said slots and means for securing said bars in place, the spacing of said bars around the periphery of the plug body corresponding to thespacing ofthe contact elements around the periphery of said jack shell whereby when the plug isl inserted a predetermined distance into the jack the Various conducting bars will engage the various contact elements, respectively, to connect circuits through the plug and jack, the conducting bars successively engaging the said different groups of circuit-controlling contact members as the plug is inserted to obtain a desired sequence of operations.

5. Switchboard plug and jack structure comprising a supporting framework, a jack comprising a hollow cylindrical shell of insulating material, said shell having one end thereof secured to the supporting framework and forming the front opening of the jack for receiving a plug, a plurality of circuit-controlling contact members mounted on the outer surface of said jack shell and spaced around the periphery ofsaid shell, said shell having apertured portions therein adjacent to said contact members', said contact members having contact elements projecting throughk said apertured portions-into the interior of said shell and movable within said apertured portions, a plug comprising a body of insulating material adapted to b-e inserted in saidljack shell, said plug body having a plurality of longitudinally extending slots in the outer surface thereof and spaced around the periphery of said body, conducting bars disposed in said slots and means for securing said bars in place, the spacing of said bars around the periphery of the plug body corresponding to the spacing of the contact elements around the periphery of said jack shell whereby when the plug is inserted a predetermined distance into the jack the various conducting bars Will engage the various contact elements, respectively, to connect circuits through the plug and jack.

6. Switchboard jack structure comprising a shell having one end thereof forming the front opening of the jack for receiving a plug with contact members thereon, a plurality of circuit-controlling contact members mounted on the outer surface of said jack shell and spaced around the periphery of said shell, said shell having apertured portions therein adjacent to said contact members, said contact members having contact elements projecting through said apertured portions so as to form protruding contacts in the interior of said shell and movable Within said apertured portions by the Contact members on said plug when the latter is inserted into the jack.

7. Switchboard plug structure comprising a body of insulating'material adapted to be inserted in a jack having contact elements mounted so as to form protruding contacts in the interior of said jack, said plug body having a plurality of longitudinally extending slots in the outer surface thereof and spaced around the periphery of said body, conducting bars disposed in said slots and means for securing said bars in place, the spacing of said bars around the periphery of the plug body corresponding to the spacing of the contact elements of said jack whereby when the plug is inserted into the jack the various conducting bars will engage the various jack-contact elements, respectively, to connect circuits through the plug and jack, said conducting bars having recessed portions in the surfaces thereof for receiving said contact elements when the plug is inserted into the jack.

8. Switchboard plug structure comprising a body of insulating material adapted to be inserted-in a jack having contact elements, said plug body having a plurality of longitudinally extending slots in the outer surface thereof and spaced around the periphery of said body, conductingy bars disposed in said slots and means for securing said bars in place, the spacing of said bars around the periphery of the plug body corresponding to the spacing of the contact elements of said jack whereby when the plug is inserted into thejack the various conducting bars will engage the variousjack contact elements, respectively, to connect circuits through the plug and jack, said plug having an insulating member secured to one end thereof, said insulating member having openings therethrough, conductors passing through said openings and connested krespectively to said conducting bars, insulating sleeves around said conductors, alternate ones ofsaid openings having recessed portions for receiving the ends of said insulating sleeves thereby to increase the leakage path between adjacent ones of said conductors. 

